KR20100106325A - Method and apparatus for determining acetabular component positioning - Google Patents

Abstract

The mechanism for establishing the orientation of the pelvic framework includes a tripod, the tripod having an angular adjustable guide rod thereon. The tip portions of the leg portions form a plane, and the guide rod is set in the preferred orientation for this plane by the surgeon based on presurgical studies. In use, two of the leg portions of the instrument are positioned by a surgeon at a defined anatomical location on the pelvis (eg, a point in the posterior / lower tibia region and a point on the anterior iliac spine). The third leg portion is then placed on the pelvis at a point determined by the location of the first two points as well as by the distance between the third leg portion and the other two leg portions. This distance is adjustable, but is preferably a determined percentage of the distance between the first leg portion and the second leg portion. The position of the guide rod then defines the direction for insertion of the artifact with respect to the actual pelvis.

Description

METHOD AND APPARATUS FOR DETERMINING ACETABULAR COMPONENT POSITIONING}

FIELD OF THE INVENTION The present invention relates to determining the osteoclast element positioning and provides a method and apparatus for quickly and accurately determining such positioning.

Malpositioning of the osteoblast elements during hip arthroplasty can lead to dislocations, impingement, abrasion and reoperation for all these problems. Proper positioning of the osteoblast elements during hip surgery requires the surgeon to know the position of the patient's pelvis during the surgery so that the element can be inserted into the proper position relative to the pelvis. However, the position of the pelvis of the patient varies widely during surgery and varies from patient to patient. Therefore, a large error occurs in element positioning when the surgeon assumes that the patient's pelvis is positioned in front of the operating table while the patient's pelvis is in the lateral position or the flat lying position. For example, one study showed that the patient's pelvis was misplaced in the range of 33 degrees around the medial lateral axis, 47 degrees around the longitudinal axis, and 17 degrees around the anterior-posterior axis. Chow JC, Eckman K, Zaramaz B, Murphy S, Intraoperative pelvic position during hip arthroplasty using computed tomography / x-ray matching Assessment, International Society for Computer-Assisted Orthopedic Surgery, 2008]

To reduce the likelihood of urea misplacement, the position of the pelvis can be tracked using computer assisted surgical navigation system technology, but most surgeons do not use this technology. More basic surgical techniques include qualitative assessment of the location of the coronal elements as compared to local peripheral bone tissue and soft tissue anatomy that can be seen through an incision. For example, one such technique originally uses transverse osteocytic ligaments as a qualitative marker of the orientation of the osteocytes. [Archbold HA, Mockford B, Mollloy D. D), McConway J, Ogonda L, Beverland D, Transverse Osteo ligament: Aids for Orientation of the Osteoblast Elements During Initial Total Hip Replacement: Postoperative A Preliminary Study of 1000 Cases Investigating Stability, J Bone Joint Surg BR. 2006, July; 88 (7): 883-6)]

However, this technique has limited accuracy for several reasons. First, because the transverse coronary ligament is very close to the center of the coronal sphere, a small geometric error in the interpretation of this position can result in a large angular error in the orientation of the coronal component. Secondly, because the transverse tibial ligaments form lines, which are two-dimensional geometric elements, they do not provide actual three-dimensional guidance. Third, because most worn hips are deformed, finding clues from local deformities is basically a defective concept. In addition, even when the local structure is not abnormal, the original tibial bone is often oriented in a position far more perpendicular to the artificial tibial bone, as may be the case with patients with femoral head osteonecrosis. Thus, although the normally formed original bone can provide clues as to where to place the artificial bone, the artificial bone is not positioned in the same orientation as the normal original bone.

If the relationship of the local structure is known for the overall orientation of the pelvis itself and the spino-pelvic composite (such as the anterior pelvic plane), the local bone structure may be used to determine the placement of the artificial bone element. have. Conversely, if this relationship is unknown, the local osteoclast structure cannot be reliably used to determine the location of the artificial osteoclast element. It is contemplated that the structure of the ipsilateral hemipelvis, rather than the local osteoclast structure, should be used to guide the positioning of the artificial osteoclast elements.

The use of ipsilateral mating pelvic structures to guide the orientation of the artificial osteoclast elements has several advantages over using local structures. First, the osteoblasts themselves, but not the pelvis, are typically changed by aging progression. Secondly, the parts of the opal pelvis are relatively far from the center of the tibia, so that a small error in positioning based on the farther pelvic bone results in a very small error in the orientation of the tibial element. Third, there is a wide range of changes in the local structure due to aging progression or malformations, but relatively small variations in the pelvic structure, which can be easily studied by CT imaging or planar radiographs, or statistically. Can be predicted.

It can be seen that there are three points that can be used to install the instrument in the ipsilateral paired pelvis to assist in solving the problem of positioning the hip bone during hip arthroplasty. These three points form the ipsilateral mating plane. These three points may be any three points on the ipsilateral opal pelvis that are spaced apart from each other, but the ideal combination of points is within the region of the sciatic bone connected to the posterior wall of the tibia, the anchor point herein. The first point P ₁ , referred to as), is included. Ease of identification of these points through most incisions for hip surgery, resistance to changes due to aging progress, and reliable consistency of location and formation (other than most surgical measures performed during reconstructive surgery), Even in the hip joint, which is a seriously malformed deformity, this makes it an ideal position for fixation.

The second point P ₂ used to form the ipsilateral opal pelvic plane is located on the lateral surface of the iliac wing, immediately adjacent to the anterior iliac spine. Such locations are generally commonly used locations, but their use in the current application is original. Anterior iliac vertebrae are frequently used reference points for a number of operations in orthopedic surgery. In clinical examination, it is often used as a proximal landmark to measure leg length. In combination with the contralateral proximal iliac spine, the position of the pelvis about the anterior and posterior axes is determined so that internal and external rotation or adduction and abduction of the hip joint can be measured clinically. have. In surgery performed in the lying down position, the abduction of an artificial cup can be roughly assessed against the horizontal line drawn between two anterior iliac spines. In image-free computer-assisted surgery, the overall pelvic plane can be determined by digitizing two proximal iliac spines and pubic symphysis. In image-based computer-assisted surgery, the location of the anterior superior iliac spine can be used as one of several points to perform registration on a CT dataset obtained prior to surgery.

As with other uses of the anterior iliac spine, the preferred location of P ₂ on the surface of the lateral iliac bone very close to the anterior iliac spine is such that this area can be easily palpable by the surgeon and is in contact with the bone. An advantage is the fact that it can be more accurately facilitated by a sharp instrument. However, in contrast to other general uses of the anterior iliac pelvic region, this point is used as one of three points forming the ipsilateral bielvic plane. The distance between P ₁ and P ₂ can be calculated from CT studies, predicted from X-ray or other imaging data, or measured directly by the surgeon at the time of surgery. This may be determined by the surgeon when he / she selects this predetermined point on the long bone, or available or future statistics of the pelvic structure taking into account such factors as age, weight, sex, race, health and other factors. It can be chosen based on the study.

It can be seen that three degrees of freedom are required to define the spatial orientation of P ₂ , one of which is uniquely determined by the bone surface itself, and one by choosing the distance (d _1-2 ) One is determined by the surgeon when he / she locates this point at a particular location on the surface and at a predetermined distance from P ₁ . The fact that the surgeon defines only one of these three factors needed to identify the space of P ₂ makes this point very reliable in identifying and makes it very resistant to changes or serious errors. .

The third point P ₃ , which forms the ipsilateral opal pelvis plane, can be located anywhere on the ipsilateral opal pelvis. In terms of both the hydraulic and physical stability of the instrument designed to be installed on these points, within the area where no vital structure is found, the instrument installed on this point is typically relatively inadvertent to penetrate the bone. As far as possible, as long as P ₃ can be appropriately carried out within the range of the pelvic surface, in the area of the dense bone and in the area where the bone surface is at least locally relatively flat so that the instrument installed at this point on the surface does not slip. It is best to be spaced apart from (1 and 2).

All three of these points provide very reliable information regarding the position of the ipsilateral pelvis and thus the position of the entire pelvis, so that the mechanical instruments installed at these three positions ensure that the proper relative orientation of the tibial element itself during surgery. Provide a guide for

으로서 제시되도록 P₃를 P1과 P2 사이의 거리(d_1-2)의 지정 비율 "r"로 위치시킴으로써 매우 간단히 확립될 수 있음을 알 수 있으며, 연산자

는 곱셈을 표시한다. 이와 유사하게, P₂과 P₃ 사이의 거리(d_2-3)는

으로서 제시되고, 마찬가지로 r'는 P₁과 P₂ 사이의 거리(d_1-2)의 지정된 비율이며, r 및 r'는 동일하거나 상이한 비율일 수 있다.The position of P ₃ can be established in various ways, but the distance between P ₁ and P ₃ (d _1-3 )

It can be seen that it can be very simply established by placing P ₃ at the specified ratio "r" of the distance (d _1-2 ) between P1 and P2 to be presented as

Denotes multiplication. Similarly, the distance between P ₂ and P ₃ (d _2-3 ) is

R 'is likewise the specified ratio of the distance d _1-2 between P ₁ and P ₂ , and r and r' may be the same or different ratios.

임을 알 수 있다. P₃와 점들(1 및 2) 사이의 임의의 비율 또는 이 비율의 조합이 충분할 수 있지만, 대략 이러한 크기의 비율은 다른 위치설정에 의해 손상될 수도 있는 생명 구조체로부터 이격되는 방향으로 신뢰성있게 P₃를 위치시킨다. 또한, 이러한 방식으로 점들의 충분히 이격되는 간격을 제공하는 것은 이들에 설치된 기구에 내재적(intrinsic) 안정성을 제공한다. 또한, P₃의 세 자유도 중에서, 하나는 P₁으로부터의 거리에 의해 지정되고, 두번째는 P₂으로부터의 거리에 의해 지정되고, 세번째는 뼈 자체의 표면에 의해 지정된다. 따라서, P₃의 위치는 수술 기구 및 뼈 표면에 의해 완전히 결정되며, 외과의사에 의하여 가변적인 해석을 받지 않는다.The ratios r, r 'from about 70% to about 100% of the length d ₁₂ almost always place P ₃ on the flat surface of the long bone, near the sciatic notch and on the generally solid bone. Within this range, a ratio of about 90% is most satisfactory and both r and r 'are nearly identical, i.e.

It can be seen that. Any ratio between P ₃ and points 1 and 2 or a combination of these ratios may be sufficient, but approximately this proportion of size is reliably P ₃ in a direction away from the living structure that may be damaged by other positioning. Locate it. In addition, providing sufficiently spaced spacing of the points in this manner provides intrinsic stability to the instrument installed therein. Also, of the three degrees of freedom of P ₃ , one is designated by the distance from P ₁ , the second by the distance from P ₂ , and the third by the surface of the bone itself. Thus, the position of P ₃ is completely determined by the surgical instrument and bone surface and is not subject to variable interpretation by the surgeon.

As discussed above, the three points form an ipsilateral pelvic plane. The orientation of this plane relative to a standard reference plane, such as all of the pelvic planes, can be readily determined from CT or other 3D imaging methods, X-ray images by means, statistics or other known techniques. Thus, the orientation of the artificial element defined in relation to this ipsilateral opal pelvic plane can also be readily converted to an orientation with respect to other planes, such as the all-pelvic plane, which is the standard for pelvic surgery.

For example, prior to surgery, it can generate a three-dimensional model of the patient's pelvis and hip joints based on a medical image such as CT or MR, and in a general manner (typically, pubis bonding or pubic nodule and right and left anterior) From the model, the anterior pelvic plane (APP) is defined. This is the reference plane commonly used by surgeons because landmarks can be easily promoted to show the association of CT images with the anatomy of the patient. The ipsilateral plane is then on the 3D model according to the invention, ie a third point on the long bone, spaced apart from the first point in the area of the posterior posterior bone, the second point adjacent to the anterior iliac spine and two other points. Defined in the phase. As noted above, the third point is about 0.7 to 1.0 times the distance between the first and second points, preferably about 0.9 or 0.8 times, away from the first and second points. It can be seen that it is advantageous. Although the spacing between the first and third points and between the second and third points does not necessarily need to be the same, it can be seen that almost the same spacing is generally effective.

To assist the surgeon in defining the desired orientation of the artificial tibial bone with respect to the ipsilateral pelvic plane, once the fixation point P1 is selected by the surgeon to determine the position of P ₂ and P ₃ A mechanism has been devised to make things happen quickly and accurately. The instrument is basically a tripod, ie it has three legs that form an ipsilateral pelvic plane for each point. In use, the first leg portion is positioned by the surgeon at a fixation point on the pelvis. The second leg portion is positioned at a selected point P ₂ on the pelvis by the surgeon. The third leg portion is adjusted to extend the selected distance or distance from both P ₁ and P ₂ on the pelvis, thereby establishing the position of P3.

The osteophoric direction guide is then located on a tripod. The guide is adjustable in any desired orientation with respect to the tip of the tripod leg portion (which coincides with three points on the pelvis when the instrument is seated on the pelvis). The orientation of the tibial directional guide is selected by the surgeon to provide the preferred orientation for insertion of the artificial element. The guide itself may be used to guide the orientation of the osteoclast element, or the guide may be used to guide the insertion of a pin into the pelvis, guiding the ultimate insertion of the artificial element in the selected orientation.

Tripods can take many forms. For example, it may take the form of a camera tripod with three leg portions branching out of a central socket that can adjust the angle between each pair of leg portions (and thus the distance between their tip portions). Preferably, however, it takes the form of a generally planar frame, with two arm portions extending generally from a common hub and oriented at an angle to each other. Legs located on the hub and each arm portion each extend outwardly from the planar frame. Advantageously, the leg portions extend perpendicular to the plane of the frame and are preferably the same length. The tips of the leg portions contact the pelvis, thereby establishing three points that form the pelvis plane.

In one embodiment of the invention described herein, the tripod takes the form of a pair of extendable arm portions branching out of the central hub, the arm portion being pivoted about the center hub, similar to the drafting compass. The length of the arm portions is adjustable by the surgeon, such as the angular opening between them. The three leg portions extend vertically from the plane formed by the arm portions, with one leg portion extending from the central hub and the other two leg portions extending from the ends of the arm portion.

In another embodiment of the invention, the tripod takes the form of a pair of extendable arm portions branching out of the central hub at a determined angle, but basically the same as the embodiment just described.

In another embodiment, the leg portion located at P ₁ is a hollow leg portion slid above the guide pin that is punctured or screwed into the bone at P1. In use, the surgeon first secures the guide pin in the bone at a predetermined position and then slides one of the leg portions of the tripod instrument over the guide pin. This secures the instrument. Leg portions located at P ₂ and P ₃ are sharp and penetrate the skin, preferably staying firmly on the bone surface at P ₂ and P ₃ without slipping.

The following description of the present invention refers to the accompanying drawings as follows.
1 is a schematic diagram of the left pelvis showing three points for forming an ipsilateral pelvic plane in accordance with the present invention;
2 is a perspective view of a prototype instrument used to test the concepts of the present invention,
3 is a perspective view of one embodiment of a mechanism suitable for use in establishing a reference plane and orientation in accordance with the present invention;
3A is a partial view of the instrument of FIG. 3 in the 3A-3A direction of FIG. 3, FIG.
3B is a schematic diagram showing that the leg portion is coupled to the conduit,
4 is a perspective view of another embodiment of a mechanism suitable for use in establishing a reference plane and orientation in accordance with the present invention.

1 is a schematic of the right pelvis showing the three points discussed. The distance d _1-2 is a first point P ₁ (a point located on the sciatic bone, connected to the posterior wall of the tibia) and a second point located on the lateral surface of the iliac spine, immediately adjacent to the anterior iliac spine The distance between the points P ₂ . The distance d _1-3 is the distance between the first point P ₁ and the third point P ₃ (on the long bone), and the distance d _2-3 is the second point P ₂ and the third point. The distance between the points P ₃ . The distance d _1-2 is the baseline, and the distances d _1-3 and d _2-3 are set at a distance of 70% to 100% of the baseline distance, preferably about 80% to 90%. . In FIG. 1, the distances d _1-3 and d _{2-3 are} shown at about 80% to 85% of the baseline distance. In FIG. 1, the distances d _1-3 and d _{1-3 are} shown to be about the same length, but need not necessarily be as described above. These three points P ₁ , P ₂ and P ₃ form an ipsilateral plane.

The surgeon defines the preferred orientation of the artificial tibial component and alignment indicator with respect to this ipsilateral pelvic plane. This may be done directly for the ipsilateral pelvic plane so defined, or for the entire pelvic plane as established from a 3D computer model of the patient's pelvis, eg, based on CT, MR, or other images. Each particular 3D model of the patient may be the most accurate method, but based on the statistical mean of the pelvic structure and size of the patients of similar size, gender, weight, age and / or other known characteristics, the alignment index and the ipsilateral pelvic plane Other methods of determining the preferred orientation may be used.

2 is a perspective view of a circular instrument used to test the concepts of the present invention. The prototype was formed from readily available elements to quickly test this concept. This mechanism comprises a metal rod branching out of the hub 14, which includes first and second adjustable clamps 14a and 14b, respectively, which hold the arm portions 10, 12 in a tightened position in the desired position. The first and second arm portions of the form (10, 12) are provided. The arm portion 10 is formed from the rods 10a and 10b fixed to each other by the adjustable clamp 10c to enable extension of the rod 10b relative to the rod 10a to a desired position. Similarly, arm portion 12 is formed from rods 12a and 12b secured to each other by adjustable clamp 12c to allow extension of rod 12b relative to rod 12a to a desired position.

At the outer ends of the arm portions 10b and 12b are leg portions in the form of rods 16 and 18 respectively held in adjustable clamps 10d and 12d. Similarly, the leg portion in the form of a rod 20 extends from the clamp 14a. In the circle, the clamp was formed from a readily available washer and nut that can be loosened and tightened to keep the element in its desired position. Leg portions 16-20 were standard trochars with a sharp tip that extends through the patient's skin and secures a lodgment on the pelvic bone. The leg portion extended downward from the arm portions 10 and 12 and the hub 14 at the same distance, and therefore the arm portion was essentially in a plane parallel to the plane formed by the tip portion of the leg portion.

The leg portion is shown positioned on the pelvic anatomy model for performing a surgical procedure on the right tibia. The first leg portion 16 rests on a point P1 which is a fixed point located on the sciatic bone, which is connected to the posterior wall of the tibia. The second leg portion 18 rests on a point P2 located on the lateral surface of the iliac blade, immediately adjacent to the anterior superior iliac pole, and the third leg portion 20 rests on a point P3 on the long bone. The location of this point is determined by the length of the arm portions 10 and 12 as set by the surgeon, as well as the relative angular orientation of this arm portion and the surface of the bone.

The direction guide portion 22 is fixedly fixed to the frame. This guide defines an orientation for the insertion of a prosthesis or for performing other surgical procedures. The orientation of the guide portion relative to the reference points P ₁ , P ₂ and P ₃ is established by the surgeon before planning or during surgery. When positioned over the patient in the manner described above, the instrument forms an ipsilateral pelvic plane, with which the orientation of the guide 22 can be easily established by imaging, direct measurement, or other known means. From CT or other imaging studies, the orientation of this plane relative to the all-pelvic plane, which is commonly used, can be determined, so that the orientation of the guide portion relative to the all-pelvic plane can be established if necessary. During subsequent surgery, when the instrument is positioned over the patient along the reference point, the guide portion provides the surgeon with a reference axis for insertion of an artifact, such as a tibia, in the desired orientation. In the circle, the guide portion was fixed to one of the arm portions (eg arm portion 12) by an adjustable clamp 24. Although the guide portion is shown in FIG. 2 as a simple solid rod, it may advantageously be a hollow tube, through which a sharp rod can be inserted into the patient. The rod is screwed into the bone, and then the instrument is removed, leaving the rod as a guide for insertion of the osteoclast element or other treatment. Alternatively, the hollow tube may be mounted parallel to the guide and the pin inserted through the tube into the patient's bone to set the preferred orientation for insertion of the element or other surgical procedure.

In use, the surgeon positions the patient in an appropriate location for the procedure to be performed. For example, during an osteoplasty of a patient's right pelvis, the patient may be placed on his or her left side, and a surgical field of sufficient size is formed to expose the right osteoclast. The surgeon selects point P1, preferably in the region of the sciatic bone, when engaging the posterior wall of the tibia. It is a fixed point and is easily located since it is generally exposed at the operating room during surgery. Leg portion 16 is located on this point. The surgeon then selects a point P2 on the lateral surface of the iliac spine, preferably immediately adjacent to the anterior superior iliac spine. This area is usually easily located by palpation and need not be in an exposed incision, but rather simply in a sterile operating room. Thereafter, the surgeon adjusts the length of the arm portion 10 (and, if necessary, the arm portion 12) to position the leg portion 18 on the P2, while the mating pelvis does not slip. On, preferably ensure that the leg part 20 lies on a relatively flat area. This forms a point P ₃ .

Positioning the first and second leg portions over the patient as described above and determining the distances d _1-3 and d _2-3 between the leg portions in the manner described above places the third leg portion of the instrument on the patient. Determine. For placement of the elements of the tibia, this point is preferably placed on the iliac bone, generally on the sciatic incision. The area where this point is located is a relatively strong part of the structure, and thus can accommodate a third leg portion which provides a stable reference plane above the patient. However, since there are no important landmarks, it does not serve as an area to help establish the criteria for the placement of elements without the aid of the apparatus of the present invention.

As already mentioned, a simple but efficient rule for adjusting the length of the arm portions 10, 12 is not only the distance between P1 and P3 (d _1-3 ) but also the distance between P2 and P3 (d _2-3 ). Is determined by the ratio of the distance d _1-2 (baseline distance) between P1 and P2. A ratio of about 70% to 100% seems to work satisfactorily, but a ratio of about 80% to 90% has been found to work well in most cases.

3 is a perspective view of another embodiment of the instrument according to the invention, which is more suitable for replication and widespread use. Turret 50 is pivotally mounted on base 52 for rotation about vertical axis 54. (It is also helpful to look at FIG. 3A, which is a partial view of the instrument from the directions 3A-3A in FIG. 3). The wings 56, 58 on the turret are centered on the horizontal axis 55 traversing the axis 54. FIG. It is mounted to the guide portion 60 for rotation in one vertical plane. The first and second extendable arm portions 62, 64 are mounted in the base 52 to rotate relative to the base and, thus, relative to each other. This allows the surgeon to adjust the angle α between the arm portions as desired. Of course, this can also be achieved due to one stationary arm part and one rotary arm part. [Also, it can be seen that both arm portions can be fixed at a set angle α.]

Extensions 62a and 64a extend from arm portions 62 and 64, respectively. Extensions 62a and 64a can be inserted from each arm portion, for example in a manner similar to that of a camera tripod, as shown in FIG. 3. Alternatively, the extensions may be mounted to slide over each arm portion or other known forms of extensions may be used. The hollow guide portions 66 and 68 are mounted at the ends of the extensions 62a and 64a, respectively. Leg portions 70 and 72 each have sharp tip portions 70a and 72a and head portions 70b and 72b respectively. The leg portion also preferably has a short boss 70c (see FIG. 3B) for mating with a corresponding groove on the inner surface of the conduits 66, 68. The leg portion extends downward to the same extent from the arm portion and the hub, so that the arm portion is basically in a plane parallel to the ipsilateral plane formed by the tip portion of the leg portion.

In use, the surgeon catches and inserts the head portions 70b and 72b of the leg portions 70 and 72 into the conduits 66 and 68 so that the bosses 70c and 72c align with the corresponding grooves in each conduit. Thereafter, he or she rotates the head portion, thereby removing the locking portion in the guide portion. In a similar manner, the leg portion 74 with the sharp tip portion 74a and the head portion 74b is removable insertable into the base 52 and removable lockable within the base 52. This structure facilitates cleaning of the instrument by enabling rapid disassembly and reassembly of the leg portions. Of course, the leg portions can also be permanently fixed to the respective arm portions.

The tip portions 70a, 72a, 74a of the leg portions 70, 72, 74 form a plane and an ipsilateral plane, respectively. The axis 54 is perpendicular to this plane, but the axis 55 is parallel to this plane. Thus, the orientation of the guide portion 60 with respect to the ipsilateral plane is the axis 55 (which defines the orientation of the azimuth of the pointer or its angle) and the axis 54 (which defines the vertical orientation of the pointer or its angle). It is defined by the orientation of the guide portion relative to). To facilitate setting or determining this angle, a scale (not shown) may be attached to the turret 50 and the base 52 or displayed on the turret 50 and the base 52.

The instrument of FIG. 3 is used in the same manner as the instrument of FIG. 2, that is, for surgery on the right hip, the tip portion of the leg portion 70 is located on the selected point P1, The tip portion is located on the selected point P2 and the length of these leg portions (as well as the angle α, if appropriate) is adjusted so that the tip portion of the leg portion 74 is preferably on the mating pelvis, preferably relatively flat. Being located within the area ensures to establish the point P ₃ . As such, this orientation of the instrument reproduces the ipsilateral plane defined in the preoperative study. The guide portion 60 is then oriented with respect to the patient in a good manner when set at an angle determined to be desirable in the preoperative study. This can then be used to guide the element insertion tool along the proper direction. To do this, the surgeon can simply visually align the tool with the guide during insertion. Preferably, however, the guide portion 60 is hollow and the elongated pin extends downwardly in the guide portion while in the desired position above the patient, after which the pin is fixed into the patient. The instrument can then be removed and the pin maintains the desired orientation for placement of the artifact.

Critical factors of the instrument can be effectively tailored to each patient within a very short period of time where the instrument takes only one or two minutes and can be easily adjusted to be done while the instrument is disinfected on the operating table. Important adjustments are the length of the arm portions 62 and 64, the angle between these arm portions and the orientation of the alignment indicators. The angle (alpha) between the arm part 1 and the arm part 2 is adjustable, but the preferred angle can be fixed at approximately 67.5 degrees, which means that the distances between P1 and P3 and between P2 and P3 are both P1 and It is an angle formed when 0.9 times the distance between P2. Similarly, although the lengths of the arm portions 60 and 62 need not be the same, a preferred embodiment of the instrument is that arm portions 1 and arm portions 2 vary in length from one to the next. This is to have approximately the same length with respect to each other.

The patient-specific adjustable parameter for each operation is then the length and alignment index of the arm portion or the orientation of the guide relative to the plane of the instrument body. The length of the arm portion may be determined prior to surgery or even during surgery using multiple methods, each with a different precision. The most precise method of determining the desired length of the arm portion is typically by three-dimensional images of individual lesions, by CT or MR images. In this way, points P1 and P2 can be determined by the surgeon based on a computer model, and the position of P3 can be automatically calculated as the only point lying on the bone surface at a certain distance from P1 and P2. Although less precise, potentially suitable methods of determining arm length include the following.

1. the overall average of all patients,

2. the overall average of all patients having the same sex, height, weight, diagnosis,

3. Statistics expected from measurements of augmented and corrected radiographs of patients under treatment, and statistics of radiographs and three-dimensional reproduction films of similar patients with these radiographs and other methods of generating CT, MR, or three-dimensional models. Academically matched, this method may be referred to as 2D to 3D statistical modeling, or

4. During surgery, the distance between P1 and P2 is measured directly, which can also be done using the instrument itself.

Next, the orientation of the alignment indicator with respect to the plane of the instrument body must be determined. This decision is based on two or more factors. The first is the relative orientation of the pelvic planes P1, P2, P3 with respect to the entire pelvis and / or the entire pelvis plane. Second, in the case of a tibial cup replacement surgery, the surgeon's preferred cup position relative to the entire pelvis and / or the entire pelvic plane. Finally, additional variables include adjustments for the expected orientation of the entire pelvis to various activities and positions after surgery. This third variable is mentioned because there is a difference in the way the pelvis of the various patients is oriented, some with more inclined pelvis, and some with less inclined pelvis. [Klingenstein G, Eckman K, Zaramaz B, Murphy S. Pelvic tilt before and after total hip arthroplasty, International Society for Computer Assisted Orthopedic Surgery, 2008] This is especially true for patients with a fused lumbar spine. If individual postoperative pelvic orientation can be expected before surgery, then this factor can be included in the planning of the desired orientation of the alignment indicator.

As with the length of the arm portion, the orientation of the alignment indicator can be determined by the above in combination with the anatomical knowledge of the pelvis of the individual patient, assisted by the determination of one or more of the factors described above.

Using these methods of adjusting the instrument body, adjusting alignment indicators, and applying the instrument during surgery, the preferred orientation of the tibial component can be determined quickly and reliably during surgery. In addition, this method often prevents the unreliable effects of local structures that are deformed and further twisted by aging progression.

4 shows another embodiment of the present invention in which the extendable arm portion is formed by a sliding beam and the conduit holding the leg portion is self-removable for ease of cleaning. In particular, the instrument is first and second formed from first and second arm part segments 102a and 104a which are secured to and extend from the hub, respectively, in the shape of a cylindrical conduit 105 having a central bore extending therethrough. Arm portions 102 and 104 are provided. The marks 102c and 104c on the arm segment 102b and 104b respectively indicate the extent of extension of the arm segment. In the configuration shown, the arm segment 102a, 104a is advantageously positioned at about 67.5 degrees, at a fixed angle relative to each other.

The mating rod segment 110 with the leg portion 116 extending from the mating rod segment slides into the conduit 105 but is removably press fit to form one leg portion of the tripod 100. Similarly, rod segments 106 and 108 having leg portions 112 and 114 respectively extending from the rod segments into hollow bore conduits 107 and 109 formed on the ends of arm portions 102b and 104b, respectively. Each slides but is press fit to remove. Removal of the leg portions facilitates disinfection of the instrument before each use, and also makes the instrument more compact for storage.

The first plate 120 is fixed to the hub 105, which has a scale 120a thereon. The second plate 122 is pivotally mounted on the hub 105 for rotation in a horizontal plane about the vertical axis 124 with respect to the first plate 120. A releasable lock 123 locks each orientation of the plate in the orientation set by the surgeon. Guide 128 is pivotally mounted on the second plate for rotation in a vertical plane about horizontal axis 126. The plate 120 has a scale 120a to indicate the respective orientation (azimuth angle) of the plate 122 relative thereto. Similarly, plate 122 has a scale 122a for indicating the angular orientation (top and bottom angle) of guide 128 with respect to the plate. As in the previous case, the tips 112a, 114a, 116a of the leg portions 112, 114, 116 each form a plane (the ipsilateral pelvic plane), and the arm portions 102 and 104 are parallel to this plane. . Thus, the orientation of the guide can be applied in this plane and thus, if necessary, all in the pelvis plane.

In such an embodiment, the conduits 112, 114, 116 may be detached from the arm portions 102 and 104 and the hub 105, respectively. Advantageously, other means of connation may be used, but the conduit may simply form a force-fit. This facilitates disinfection of the instrument for repeated use while allowing easy reassembly in the operating room. In addition, the instrument can be stored in a more compact package.

In another variation of the mechanism of FIG. 4, the leg portion 112 may actually comprise a hollow conduit of the same length as the leg portions 114 and 116 rather than being one of the leg portions, such as a removable one. With this configuration, the surgeon first selects a fixed point P ₁ , inserts a sharp rod (cart) into the fixed point, slides the hub 106 onto the rod, and then the instrument frame is moved from the hip during positioning. Position the leg portion as described above while ensuring that it is not sliding.

Another variant of the use of the instrument includes a combination with computer assisted surgical navigation using optical, electromagnetic, or other tracking means. In any such process, a coordinate system for the pelvis must be formed, all of which are pelvic planes or other planes. Since the hydraulic relationship between the ipsilateral pelvis plane as formed by the mechanical instrument and any other plane, such as the entire pelvic plane, can be determined preoperatively, the placement of the instrument onto the ipsilateral bilateral pelvis and subsequent positioning with the navigation system The measurement can be used to quickly determine the orientation of the pelvis. The mechanical instrument can then be removed and surgical navigation can proceed as usual.

Similarly, surgical navigation can be facilitated by using the same method as described above but by quickly determining the overall orientation of the pelvis through a virtual mechanical instrument. In this way, P1 is determined by the surgeon using a digitizing device (optical, electromagnetic, etc.). Next, the surgeon defines P2 using a digitizing device. The virtual instrument defines a P1-P2 distance, so P2 must lie on a sphere with a radius P1-P2 and also on a bone surface. Thus, two of the three degrees of freedom for determining point P2 are predetermined and only one of the three degrees of freedom for determining point P2 is selected by the surgeon. This greatly improves the accuracy of determining this point. Finally, the surgeon defines P3 using a digitizing device. Using a virtual instrument, the position of P3 must lie on the bone surface, must be a certain distance from point P1, and a certain distance from point P2. Thus, the virtual mechanical instrument defines all three degrees of freedom for determining the position of point P3 and the position of point P3 is not selected by the surgeon. In addition, this very specific point can be determined on a flat and indistinguishable surface, without any detectable landmark.

Claims are as follows.

Claims (34)

A frame having at least three leg portions disposed on the object to define a reference plane for the object,
A guide positioned on the frame to define an orientation with respect to the frame
Device for orienting a surgical instrument. The method of claim 1 wherein the distance between at least two of the leg portions is adjustable.
Device for orienting a surgical instrument. The method of claim 2, wherein the distance between at least three of the leg portions is adjustable.
Device for orienting a surgical instrument. The method of claim 2 or 3, wherein the respective orientations between the first and second pairs of leg portions are adjustable.
Device for orienting a surgical instrument. The apparatus of claim 1, wherein the guide portion is mountable on the frame and adjustable in angular orientation with respect to the plane defined by the leg portions of the frame.
Device for orienting a surgical instrument. 6. The apparatus of claim 1, wherein the guide comprises a hollow tube.
Device for orienting a surgical instrument. 7. The hollow tube of claim 6, comprising a hollow tube parallel to said guide for receiving an elongated pin that is insertable into the subject through the hollow tube at a location determined by the surgeon.
Device for orienting a surgical instrument. 7. The elongated pin of claim 6, wherein the guide portion receives an elongated pin that is insertable into the object through the tube.
Device for orienting a surgical instrument. The method of claim 1, wherein when the first leg portion of the leg portion is located in the region of the lower posterior bone of the subject and the second leg portion of the leg portion is located in the region of the anterior superior iliac bone of the subject, thereby, the third leg By placing the leg on the long bone of the subject, the leg portions of the device can be adjusted such that a plane in which the surgical instrument can be oriented is defined.
Device for orienting a surgical instrument. 10. The apparatus of claim 9, wherein the leg portions are adjustable such that the distance between at least one pair of the leg portions is a predetermined ratio of the distance between other pairs of the leg portions.
Device for orienting a surgical instrument. The method of claim 10, wherein the ratio is on the order of 70% to 100%
Device for orienting a surgical instrument. The method of claim 10, wherein the ratio is on the order of 90%
Device for orienting a surgical instrument. The method of claim 11, wherein the ratio is determined according to object specific data obtained from a CT scan.
Device for orienting a surgical instrument. The method of claim 11, wherein the ratio is determined according to object specific data obtained from X-rays.
Device for orienting a surgical instrument. The method of claim 11, wherein the ratio is determined according to a combination of object specific data obtained from X-rays and statistical data defining a distance relationship between the tibia and the sciatic bone.
Device for orienting a surgical instrument. To orient the surgical instrument relative to the pelvis of the subject,
Positioning the first leg of the tripod in the region of the posterior posterior bone of the subject,
Positioning a second leg portion of a tripod in the region of the anterior superior iliac pole;
Positioning a third leg portion of a tripod on the long bone of the subject,
The end of the leg portion contacts the subject, thereby defining a plane in which the surgical instrument can be oriented relative thereto.
A method of orienting a surgical instrument relative to a pelvis of a subject. 17. The device of claim 16, wherein the first leg portion is located adjacent to the tibial rim and outside of the tibial rim.
A method of orienting a surgical instrument relative to a pelvis of a subject. 18. The device of claim 17, wherein the leg portions are spaced apart from each other by a defined distance from each other.
A method of orienting a surgical instrument relative to a pelvis of a subject. 19. The method according to claim 18, wherein the distance between the first leg portion and the third leg portion is adjustable to be a defined ratio of the distance between the first leg portion and the second leg portion.
A method of orienting a surgical instrument relative to a pelvis of a subject. The method of claim 19, wherein the ratio is determined in accordance with object specific data obtained from a CT scan.
A method of orienting a surgical instrument relative to a pelvis of a subject. The method of claim 19, wherein the ratio is determined according to object specific data obtained from X-rays.
A method of orienting a surgical instrument relative to a pelvis of a subject. 20. The method of claim 19, wherein the ratio is determined according to a combination of object specific data obtained from X-rays and statistical data defining a distance relationship between the tibia and the sciatic bone.
A method of orienting a surgical instrument relative to a pelvis of a subject. Method of matching a surgical navigation system to a subject,
Positioning the first leg of the tripod in the region of the posterior posterior bone of the subject,
Positioning a second leg portion of a tripod in the region of the anterior superior iliac pole;
Positioning a third leg portion of a tripod on the long bone of the subject,
The end of the leg portion contacts the object, thereby defining a plane in which the navigation system can be oriented with respect to it.
Surgical navigation system registration method for the subject. 24. The method of claim 23, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from a CT scan.
Surgical navigation system registration method for the subject. 24. The method of claim 23, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from an X-ray scan.
Surgical navigation system registration method for the subject. 24. The method of claim 23, wherein the orientation of the navigation system is determined with respect to the plane according to a combination of object specific data obtained from X-rays and statistical data defining an estimate of the three-dimensional surface structure of the pelvis and pelvis. Including more steps
Surgical navigation system registration method for the subject. Method of matching a surgical navigation system to a subject,
Aligning the first point within the region of the posterior posterior bone of the subject,
Registering a second point within the region of the anterior iliac bone of the subject;
Registering a third point on the sciatic bone of the subject,
The points define a plane in which the navigation system can be oriented relative to it.
Surgical navigation system registration method for the subject. 28. The method of claim 27, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from a CT scan.
Surgical navigation system registration method for the subject. 28. The method of claim 27, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from an X-ray scan.
Surgical navigation system registration method for the subject. 28. The method of claim 27, further comprising determining an orientation of the navigation system with respect to the plane according to a combination of object specific data obtained from X-rays and statistical data defining an evaluation of the three-dimensional surface structure of the pelvis and pelvis. Containing
Surgical navigation system registration method for the subject. A method for matching a surgical navigation system to a subject, including a virtual instrument,
The first of the three or more points is digitized within the area of the posterior posterior bone of the subject,
The second point is digitized within the area of the anterior iliac spine of the object at a predetermined distance from the first point,
A third point is digitized at a location on the bone that is a specific distance from a first point and a specific distance from a second point of the object,
These three points are digitized on the object, thereby defining a plane in which the navigation system can be oriented relative to it.
Surgical navigation system registration method for the subject. 32. The method of claim 31, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from a CT scan.
Surgical navigation system registration method for the subject. 32. The method of claim 31, further comprising determining an orientation of the navigation system with respect to the plane in accordance with object specific data obtained from an X-ray scan.
Surgical navigation system registration method for the subject. 32. The method of claim 31, further comprising determining an orientation of the navigation system with respect to the plane according to a combination of object specific data obtained from X-rays and statistical data defining an evaluation of the three-dimensional surface structure of the pelvis and pelvis. Containing
Surgical navigation system registration method for the subject.

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